708 



SCIENCE. 



[N. S. Vol. I. No. Sff. 



method would, probably, be preferred, espe- 

 cially by cliemists who are familiar with 

 operations conducted in red-hot tubes. 



I have here another experiment illustra- 

 tive of the reaction between magnesium 

 and nitrogen. Two rods of that metal are 

 suitably mounted in an atmosphere of nitro- 

 gen, so arranged that we can bring them 

 into contact and cause an electric arc to 

 form between them. Under the action of 

 the heat of the electric arc the nitrogen will 

 combine with the magnesium; and if we 

 had time to carry out the experiment we 

 could demonstrate a rapid absorption of 

 nitrogen by this method. When the ex- 

 periment was first tried, I had hoped that 

 it might be possible, by the aid of electricity, 

 to start the action so effectively that the 

 magnesium would continue to burn inde- 

 pendently under its o^vn developed heat in 

 the atmosphere of nitrogen. Possibly, on 

 a larger scale, something of this sort might 

 succeed, but I bring it forward here only 

 as an illustration. We turn on the electric 

 current and bring the magnesiums together. 

 You see a brilliant gi-een light, indicating 

 the vaporisation of the magnesium. Under 

 the influence of the heat the magnesium 

 burns, and there is collected in the glass 

 vessel a certain amount of brownish-looking 

 powder which consists mainly of the nitride 

 of magnesium. Of course, if there is any 

 oxygen present it has the preference, and 

 the ordinary white oxide of magnesium is 

 formed. 



The gas thus isolated is proved to be inert 

 by the very fact of its isolation. It refuses 

 to combine under circumstances in which 

 nitrogen, itself always considered very inert, 

 does combine — both in the case of the 

 oxygen treatment and in the case of the 

 magTiesium treatment ; and these facts are, 

 perhaps, almost enough to justify the name 

 which we have suggested for it. But, in 

 addition to this, it has been proved to be 

 inert under a considerable variety of other 



conditions such as might have been expected 

 to tempt it into combination. I will not 

 recapitulate all the experiments which have 

 been tried, almost entirely by Professor 

 Ramsay, to induce the gas to combine. 

 Hitherto, in our hands, it has not done so; 

 and I may mention that recentlj^, since the 

 publication of the abstract of our paper read 

 before the Royal Society, argon has been 

 submitted to the action of titanium at a red 

 heat, titanium being a metal having a great 

 affinitjr for nitrogen, and that argon has re- 

 sisted the temptation to which nitrogen 

 succumbs. We never have asserted, and we 

 do not now assert, that argon can under no 

 circumstances be got to combine. That 

 would, indeed, be a rash assertion for any 

 one to venture upon ; and only withiu the 

 last few weeks there has been a most in- 

 teresting announcement by M. Berthelot, 

 of Paris, that, xinder the action of the silent 

 electric discharge, argon can be absorbed 

 when treated in contact with the vapor of 

 benzine. Such a statement, coming from 

 so great an authority, commands our atten- 

 tion; and if we accept the conclusion, as I 

 suppose we must do, it will follow that 

 argon has, under those circumstances, com- 

 bined. 



Argon is rather freelj^ soluble in water.. 

 That is a thing that troubled us at first in 

 trying to isolate the gas ; because, when one 

 was dealing with very small quantities, it 

 seemed to be always disappearing. In trj-- 

 ing to accumulate it we made no progress. 

 After a sufi&cient quantity had been pre- 

 pared, special experiments Avere made on 

 solubilitj' of argon in water. It has been 

 found that argon, prepared both by the 

 magnesium method and by the oxygen 

 method, has about the same solubility in 

 water as oxygen — some two-and-a-half times 

 the solubility of nitrogen. This suggests, 

 what has been verified bj' experiment, that 

 the dissolved gases of water should contain 

 a larger proportion of argon than does at- 



